The Allen 20mm Tie On Double Dynamic Block features a stainless-steel head loop and central axle, providing maximum strength and reliability. The block's design ensures proper orientation and minimal cheek separation when loaded with a soft shackle. It can be used with or without a Tii-Shackle and should be attached using a crossed/ through threaded line for maximum strength. The block's large central rivet reduces weight and offers a rope-friendly attachment, perfect for use in a cascade system. Its patented bearing system, which uses twin rows of stainless-steel ball bearings, provides superior load-carrying ability and longevity. This block works well with 1.5mm or 2mm Dyneema rope. For further fitting advice, please contact us.